Bladder reconstruction plays an essential role in the treatment of voiding disorders characterized by low bladder capacity or high intravesical pressures or both-1 The ideal material should be biocompatible and mechanically reliable, resist extraluminal infection, deter or tolerate intraluminal infection, and be easy to implant surgically. The material should preserve renal function, provide adequate urinary storage at low pressure and allow volitional, complete evacuation of urine per urethram. To achieve this goal, autoaugmentation techniques and a great variety of synthetic and naturally derived biomaterials have been used.
Synthetic materials have been unsuccessful because of foreign-body reactions, resulting in stone formation, collapse, infection, rejection, or extrusion and migration of the graft (see Barrett, et al. Semin. Urol. 2:167-75 (1984); Bohne, et al. J. Urol. 77:725-732 (1957); Stanley, et al. J. Urol. 107:783-787 (1972); Swinney, et al. Br. J. Urol. 33:414-429 (1961)). As a result, synthetic materials have been used primarily as temporary implants to allow bladder regeneration to occur (see Taguchi, et al. J. Urol. 108:752-756 (1977); Tsuji, et al. J. Urol. 97:1021-1028 (1967)). However, the majority of studies confirm regeneration of transitional cell epithelial lining on the inner surface of the graft without adequate reconstruction of a functional detrusor muscle. Natural materials for bladder reconstruction have mostly retracted with time (see, Baret, et al. Surg. Gynec. Obstet. 97:633-639 (1953); Kelami, J. Urol. 105:518-22 (1971)) and the alloplastic total bladder prosthesis is still at an investigational stage in animals.
Autoaugmentation by enterocystoplasty with either small bowel or colon has well-documented urodynamic benefits. Sidi, et al. J. Urol. 136:1201-4 (1986). Because of complications, including metabolic acidosis (McDougal, J. Urol. 147:1199-208 (1992)) rupture (Bauer, et al. J. Urol. 148:699-703 (1992)), mucus production, chronic bacteriuria, stone formation (Golomb, et al. Urology 34:329-38 (1989)), and the potential for osteoporosis and malignancy (Filmer, et al. J. Urol. 143:671 (1990)), the search for other suitable materials continues. Gastrocystoplasty circumvents some of these problems, but peptic ulcers and perforations, the hematuria/dysuria syndrome, and metabolic alkalosis negate some of its potential advantages over intestinal segments. Mitchell, et al. Oxford, Blackwell Scientific, pp 439-444 (1993). Recently the technique for enterocystoplasty lined with urothelium has been shown to increase bladder capacity while taking advantage of the inert properties of an intact urothelial lining. Buson, et al. Urology 44:743-748 (1994); Gonzales, et al. Urology 45:124-129 (1995). Gastrointestinal segments in general have proven to enhance bladder capacity and compliance, thus protecting the upper tract and renal function. Unfortunately, they are unable to support normal micturition, which often necessitates clean intermittent catheterization or other supportive measures to ensure complete bladder evacuation.
To overcome this functional shortcoming, natural and/or biodegradable materials serving as a scaffold for the ingrowth of host bladder wall components have been tried with encouraging results. Atala, et al. J. Urol. 150:608-12 (1993); Knapp, et al. J. Endourol. 8:125-30 (1994); Novick, et al. J. Biomed. Mater. Res. 12:125-47 (1978); Scott, et al. Br. J. Urol. 62:26-31 (1988). The bladder wall tissue thus regenerated has shown the potential to provide functional augmentation in terms of an enlargement of the bladder without compromising its voiding abilities.
Despite the above efforts, there remains a need for new materials which are useful for grafting by serving as a scaffold for the development of new muscle tissue. The scaffolding material should be antigenic and capable of use in a variety of organs and individual hosts. Surprisingly, the present invention provides such materials and further provides methods for their preparation and use.